Probably won't help, but on your screen shots that you don't have the -12DB on. But I see your level is set to -17DB. Probably couldn't hurt trying it with the -12 on just to hear the difference.
Beyond that I don't see anything that leaps out. And you did say this happens on other rigs and through the Kemper headphone out.
Maybe time to contact support?
yeah I've tried to get in touch with them, but nothing yet. It's my second week as a Kemper owner... Seriously